Similarities between rabbit hepatocyte membrane and nuclear envelope as regards the binding of homologous cytophilic IgG.

Nuclei isolated from rabbit liver are able to bind cytophilic monomeric and polymeric homologous IgG while non-cytophilic rabbit IgG are not bound by nuclei even after its aggregation. The present finding suggests that the rabbit hepatocyte nuclear envelope is similar to the liver cell membrane as regards the specific binding of monomeric cytophilic IgG via a selective binding site for the Fc fragment of IgG. Therefore, the Fc receptor is not restricted to the external membrane of the hepatocyte but exists also on the nuclear envelope.